On the difficulty of making a good null mutant

http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.10...

Anderson JL, Mulligan TS, Shen M-C, Wang H, Scahill CM, Tan FJ, Du SJ, Busch-Nentwich EM, Farber SA. mRNA processing in mutant zebrafish lines generated by chemical and CRISPR-mediated mutagenesis produces unexpected transcripts that escape nonsense-mediated decay. PLoS Genet. 2017;13(11):e1007105. doi:10.1371/journal.pgen.1007105